This invention relates generally to split environmental engines and to multi-split environmental engines which are suitable for split engine crankshaft operation whereby an engine may operate on less than all of its cylinders under light load conditions and on all of its cylinders under full load conditions. This invention relates in particular to crankshaft systems for split and multi-split environmental engines comprising, in addition to such crankshafts, self-synchronizing clutches and special split balance shafts, which are newly combined with each other, and which cooperate dynamically as components of the crankshaft systems. These three components, coordinated with each other, must be taken into account when well balanced and smooth running split and multi-split environmental engines are constructed. Notable is also that all three components taken together replace the one piece crankshafts of conventional engines.
Split crankshaft engines appear to have the capacity, to reduce effectively the total amount of exhaust gases, and to reduce extensively Co.sub.2 emissions of motor vehicles, to restrain the climatic hothouse effect, to decontaminate the city air, and to reduce fuel consumption.
The major problems associated with split environmental engines and multi-split environmental engines are:
(1) the balancing of free dynamical engine forces and of free dynamical engine couples generated by the partial engines when running alone, and generated by the complete engine, when working as an aggregate; and PA1 (2)the shock free synchronization operation of the synchronizing clutches installed between the partial crankshafts.
Both of these problems have their origins in the crankshaft systems of split engines of the prior art.
Regarding the first problem of the prior art mentioned above, it is know from the dynamics of the reciprocating piston engines that an engine runs smoother as more cylinders cooperate, and runs rougher when less cylinders are in action. The split environmental engines have a small number of cylinders, particularly when the partial engines are running alone. Problems with coordination arise when the partial engines are clutched together, due to the mutual adjustments of the firing orders and of the changing dynamical forces. Balancing problems of these engines, therefore, are of special importance, and difficult corrective means are required. The means provided in the present invention are novel crankshaft designs, novel balance shafts, and specially arranged counterweights on both of said shafts.
Regarding the second problem in the prior art mentioned above, the manner in which the synchronization operation is carried out is also of importance in the design of the partial crankshafts. For example, studies have shown that a synchronization after 720.degree. relative revolution for 4-stroke engines is not always required. The present invention encompasses a crankshaft design which makes a synchronization after 360.degree. relative revolution possible, while still achieving equal firing distances and smooth running of 4-stroke engines.
A smooth running engine also embraces shock-free synchronization operation of the clutch between the partial crankshafts. In this respect the hitherto proposed clutch designs appear to be unsatisfactory. This obligation is leveled against synchronizing clutch designs relying on the principle, at which the rigid connection of the two partial crankshafts occurs during the cranking-up operation of the secondary engine by the primary engine. This might produce heavy connection shocks, which are not acceptable. This synchronizing principle is the basis of many proposed synchronizing clutches.
A careful investigation of the relative rotation motions occurring during a cranking-up and synchronizing operation of two partial crankshafts shows that there are two relative rotation directions. In the first case, and during the starting and cranking-up operation of the secondary engine by the primary engine, the primary engine advances the secondary engine in what represents the first relative rotation direction. In the second case, after the secondary engine has started firing, and with the development of its power torque, the friction clutch-part of the self-synchronizing clutch can be arranged to slide. When it is especially prepared for this by a reduced torque transferring capacity as in the present invention, by which the secondary engine advances the primary engine, and what represents the second relative rotation direction.
Accordingly, it is an object of the present invention to provide well balanced and shock-free crankshafts systems for split environmental engines and for multi-split environmental engines consisting of partial crankshafts, split balance shafts, and self-synchronizing clutches coordinated with each other, in place of the one-piece crankshafts of conventional engines, thereby ensuring a vibration-free and smooth running of the partial engines and of the complete engine.
Another object of the present invention is to provide crankshaft systems for split and multi-split environmental engines ensuring equal firing distances at the 4-stroke partial engines and the complete engine.
Yet another object of the present invention is to provide crankshaft systems for split and multi-split environmental engines ensuring a shock-free automatic synchronization of the partial crankshafts to the complete crankshafts.